A vehicle of the type described may be of the kind generally known as a back hoe excavator in which the boom comprises a main boom, which at its lower end is pivotally connected to a king post assembly for movement up and down in a vertical plane, a dipper arm, pivotally connected at the outer end of the main boom for movement in a vertical plane, said dipper arm carrying, or being adapted to carry a material handling implement such as a bucket, hydraulic rams to pivot the main boom relative to the king post for raising and lowering the main boom in the vertical plane, to pivot the dipper arm in a vertical plane relative to the main boom and to pivot the implement tool in a vertical plane relative to the dipper arm, the king post assembly being capable of pivotal movement about a vertical axis so that the main boom can be rotated or stewed from one side to the other of the center line of the tractor or other vehicle for the purpose of working to one side or the other of the vehicle. The king post assembly may be mounted upon a frame extending transversely of the center line of the tractor or like vehicle, the king post assembly being slidable or adjustable along this frame so that it can be positioned at one extreme side of the frame for the purpose of working in a direction parallel to the center line of the vehicle, such as when digging a trench or excavating, or clearing a ditch, where it is not possible to work along the center line of the tractor.
Alternatively or in addition a vehicle of the type described may be provided with a boom comprising a loader arm assembly, one end of the loader arm assembly being mounted on a support part of the body for rotation about a first horizontal axis and the loader arm assembly carrying at its other end, a material handling implement adapted for rotation about a second horizontal axis, fluid operated means being provided to rotate the loader arm assembly about the first horizontal axis and fluid operated means being provided to cause rotation of the implement relative to the loader arm assembly about the second horizontal axis. The loader arm assembly may comprise a single boom or a pair of spaced booms.
Alternatively a vehicle of the kind described may comprise a telescopic handler in which the boom comprises a plurality of boom sections which are movable longitudinally relative to each other so that the boom may be extended and in which one end of the boom is pivotally mounted on the body towards the rear of the body for up and down pivotal movement and the opposite end of the boom carrying a material handling implement.
In the past such vehicles had a transmission incorporating, for example, a four speed gearbox but with a desired increase in road speed the spacing of the gear ratios in such a gearbox became sufficiently large for the vehicle to have poor driveability. In an attempt to overcome this problem gearboxes with a larger number of ratios have been used such as five and six speed gearboxes so as give smaller steps between the gears and thus improve the driveability.
However, at higher road speeds, and because a soft torque converter match is needed on a vehicle of the kind described such a vehicle loses speed quite noticeably when called upon to climb a hill. In addition the higher road speed even on the flat also creates more drag on the vehicle. In either case there is consequently greater converter slip and therefore more heat is dissipated.
The power range of the engine may lie in the range 50 HP to 150 HP.
An object of the invention is to provide a vehicle of the type described in which the above mentioned problem is overcome or is reduced.